Air-compressor.



B. A. RIX.

AIR COMPRESSOR. APPLICATION-FILED AUG. 17, 1609.

Patented Sept. 5,1911.

Wilma/00% J M nn'vmnn n. 311:, or snn rnanorsco, CALIFORNIA.

AIR-COMPRESSOR.

Specification of Letters Patent.

Patented Sept. 5, 1911.

I Application filed August 1'7, 1909. Serial No. 513,291.

To all whom it mag concern: I

Be it known that ILEDWARD A. Rrx, citizen of the U ni'ted. States, residing in the city and county of San Francisco and State of California, have invented new and useful Improvementsin Air-Compressors, of which the following is a specification.

My invention relates to air compressors. The objectof the present invention is to provide a simple, cheap, light, practical, economically operated compressor, particularly designed to meet the demands of the lesser industrial arts as well as the greater.

Modern air compressor construction has resulted in the production of heavy, ponderous and expensive machines which are slow moving, with intricate valve mechanisms, and subject to great wear. Although such machines may be economical in operation, the first cost and the Weight of such compressors limit their field of operation.

Realizing that air is an extremely light and elastic fluid, and that in a successful com-' pressor small clearances must prevail, I have designed and put into extensive successful practice a compressor construction that is in harmony with the-fluid to be pumped, and

one whose first cost is but a small fraction of the cost of the compressors ordinarily 'in claimed, havingreference to the accompanying drawings, in which Flgurel 1s a vertical section of the nvention partly in elevation. Fig. 2 is aview of the loose valve disk. Fig. 8'is a detail of the stof) plate and piston head;

the embodiment of the invention, A represents a compressor cylinder of suitable size provided with a water-jacket 2 and with one -or more air inlets 3, which latter communicate with the annular space 4 in the cylinder casing. This annular space at is in constant communication with an annular groove. or channel. 5 in the trunk piston 6 through either the upper or lower annular ports 77' in the casing; the width of the circumferential groove 5 on the piston and the-position,lof the ports 77 being proportioned to the piston travel,'so: that practically the air is always atatmospheric pressure in space 5, and the latter s always in 0 en communication with the outer atmosp ere. This annular space 5 and thedouble set of ports 7 7 constitute one of the main features of the .present inventiomas will be more particularly explained hereinafter.

From space 5 in the piston the air passes on each alternate reciprocation of the iston, through ports 8 formed in the en of the piston, into the compression chamber 9; the ports 8-being closed during compression by the loose disk inlet valve 10. The opening movement of the disk inlet valve 10 is limited by a stop plate or a follower plate 11 screwing or otherwise secured in the head of the piston. This disk inlet valve 10 and its stop plate 11 are also important and essential features of the invention, in conjunction with the air inlet chamber 5.

12 is a discharge valve comprising a fiat casting seating on thetop end of the cylinder and normally closed by the spring 13, this valve being suitably guided, as here shown, by the walls of the counterbore 14. It will readily be seen that the piston may touch this valve at the end of the stroke and make nearly a perfect displacement, and'on account of the large periphery of the valve it need rise but a trifle to give ample discharge area, the air piston completely filling the cylinder on each up stroke, and the highest volumetric efficiency is attained.

Suitable packing rings 15-16 are placed" above and below the air inlet space, 5 to keep cause the air to rush in through the crankcase and around the bearings, drawing the oil out of the bearings and causing heating ofithe bearings. The inlet valve 10 is stamped from thin material, like tin, or Russia iron plate, and needs no spring to keep it on the seat or to close it. It iss'imply in the form of a thin, flat ring or disk loosely surrounding the central stem 17 of the stop plate 11, andhas an extremely limited play between the stop plate and the adjacent end of the piston.

The quick closing of the valve over the ports 8 is accomplished at the lower end of the stroke by making the lift extremely small, and a very important part ofthe present invention is the discovery that 1 can use a lift which. is but a small fraction of the lift common in all other pumps on the market. Ordinarily if the inlet .valve is permitted to lift any great amount, and the compressor is running at high speed, the piston will have .madequite an appreciable part of the return stroke before the-valve closes, with a consequent volumetric loss. In my compressors, of which I have put a great many on the market, I never give over 3; of an inch lift, and ordinarily of an inch, and even under some circumstances of an inch lift; the amount of lift being determined by the distance between the stop plate 11 and the end of the cylinder. By

screw-threading the stem 17 of the stop plate 11 into the piston, the amount of lift may be easilyadjusted to the requirements of a particular case. The inlet disk valve 10 and the stop plate 11 are of approximately the same diameter, the stop plate usually being a trifle wider than the disk valve, but both being of less diameter than the cylinder bore, so as to permit air readily to pass around their perimeters into the compression chamber 9. While this very small lift creates perhaps two or three ounces of vacuum in the cylinder when the piston is moving downward to suck in air, this slight vacuum is desirable because it holds the valve disk snug up against the under side of the stop plate 11, and so prevents chattering and fluttering and practically obviates wear. Such slight vacuum as is created is immediatelydlsslpated as soon as the piston reaches the lower endof its stroke and before reversing, when the cylinder is put for'an instant in communication with the atmosphere, making a perfect filling, Another important feature of this inlet valve construction 10 is that the slight lift of the valve and the opposed flat parallel surfaces afforded by the end of the piston and the under side of the stop plate 11 keep the valve at all times perfectly straight and obviate beating or warping of the valve, so that on the compression stroke the valve is always sure to seat smooth and tight. By this construction there is practically no wear on this inlet valve, and it will last indefinitely.

It is to be noted that in this compressor the spaces 45, and ports 77- are annular,

thus givinga balanced and even flow of air.

This machine has shown remarkable efiiciencyin practice, some machines running at.500 R. P. M., giving as much as 15% increased volumetric eflicien'cy over the best slow type machines with ordinary poppet valves. Furthermore, thecost to manufacture a machine is small, by reason of this valve arrangement, due to the factthat there is very little machine work necessary. I have successfully used ordinary sheet tin for my disk inlet valve 10.

Having thus described-my invention, what I claim and desire to secure by Letters Patent is I 1. In an air compressor, the combination with a cylinder having an eduction valve at its upper end and two annular series of inlet ports at an intermediate point, spaced apart longitudinally of the cylinder, of a crank shaft, a connecting rod and a piston movable downwardly to open the upper series of inlet ports above the piston and having a peripheral air chamber open to the inlet ports in all positions of the piston when the inlet ports are not open to the cylinder, whereby the inlet ports are never closed by the piston, and an upwardly opening valve in the piston through which air passes from the peripheral chamber to the cylinder.

2. In an air compressor, the combination with a piston having 'a peripheral air chamher, an upwardly opening valve for closing communication between the air chamber and space above the piston, a driven crank shaft and a connecting rod between the crank shaft and piston, of a cylinder in which the piston works having an eduction valve at the upper end and two annular series of inlet ports spaced apart longitudinally of the cylinder a distance to maintain one series open to the peripheral air chamber in the piston or to the cylinder above the piston at all times, whereby the volumetric capacity of the compressor is increased and the closing of the piston valve is facilitated.

3. An air compressor embodying a piston having a peripheral air chamber intermediate its ends closed against communication with the space below the piston and a disk check valve controlling communication between the chamber and space above the piston, of a cylinder in which the piston works having an eduction valve at the top and two annular series of inlet ports arranged in the EDWARD A: RIX.

Witnesses CHARLES A. PENFIELD, E. G. BLASDEL. 

